Biomass derived carbon electrodes with reduced graphene oxide for ultrahigh performance supercapacitor

In order to meet the growing energy demands of modern society while simultaneously reducing global warming,   the development of advanced energy generation and storage systems that are sustainable and have high efficiency... [ view full abstract ]

In order to meet the growing energy demands of modern society while simultaneously reducing global warming,   the development of advanced energy generation and storage systems that are sustainable and have high efficiency should be a priority. Supercapacitors, due to their excellent power density and long cycle life, have been considered an attractive energy storage system for emerging technologies like wearable electronic devices and hybrid electric vehicles. Among potential electrode materials for supercapacitors, activated carbons derived from renewable bio-waste appear to be a promising candidate due to their low cost and environmentally-friendly nature, as well as unique surface properties, which result from function groups containing heteroatoms. However, their use in energy storage is still limited by their low energy density, which is a formidable barrier for industrially extensive applications. Therefore, beyond the development of the active material itself, the rational design of electrodes regarding various components and their interaction and structure is recognized as crucial for the further progress of supercapacitors. In the present work, a novel electrode composed of activated carbons prepared from waste coffee grounds and single and few layered sheets of reduced graphene oxide intervening between the activated carbon particles enables the fabrication of ultrahigh performance supercapacitors. They present significantly enhanced capacitance in both aqueous and non-aqueous electrolytes, with good rate performance and cycling life stability, compared to previous devices.